维甲酸诱导基因I在DSS诱导的慢性肠炎小鼠结肠组织中的表达

Expression of RIG-I in colon tissue from DSS-induced mouse chronic colitis

目的:探讨维甲酸诱导基因I(RIG-I)在葡聚糖硫酸钠(DSS)诱导的小鼠慢性结肠炎中的表达及意义。方法:选择健康清洁级8~10周龄C57BL/6雌性小鼠,随机分为对照组(n=8,正常饮用无菌蒸馏水)和慢性炎症组(n=8),先给予10 g/L DSS溶液自由饮用7 d,然后正常饮用无菌蒸馏水14 d作为1个周期,循环3个周期后建立小鼠慢性结肠炎模型,于第70天用颈椎脱臼法处死小鼠并取结肠组织标本。肠道炎症程度通过测定结肠长度、HE染色和疾病活动指数评分等方法评估。采用荧光定量PCR技术检测小鼠结肠组织中炎性因子(IL-6、IL-8和TNF-α),IRE1α和RIG-I mRNA表达水平,免疫组化法和蛋白印迹法检测小鼠结肠组织中RIG-I、磷酸化(p)-IRE1α蛋白的表达。结果:对照组小鼠无肠炎表现,而慢性炎症组小鼠结肠出现炎症表现。与对照组相比,慢性炎症组中IL-6、IL-8和TNF-αmRNA的表达量增加,IRE1α和RIG-I mRNA表达量降低(P<0.01)。免疫组化结果显示RIG-I蛋白主要表达于小鼠结肠上皮细胞胞质及间质细胞胞质中,p-IRE1α主要在结肠上皮细胞刷状缘、浆细胞等细胞的胞质中表达,蛋白定量结果显示慢性炎症组RIG-I、p-IRE1α蛋白低于对照组(P均<0.001)。结论:RIG-I可能通过减低IRE1-RIDD-RIG-I在小鼠结肠炎的发生和发展中起重要作用。

Aim：To investigate the expression and significance of retinoic acid induced gene-I（ RIG-I） in colon tissue from dextran sulphate sodium（ DSS）-induced chronic colitis mice. Methods：C57 BL/6 mice were randomly allocated into control group and chronic colitis group（ n = 8 for each group）. Mice in the control group were given free drinking. Mice in chronic colitis group were given 10 g/L DSS for 7 days and then drinking water for 14 days as a cycle. After three cycles a mouse model of chronic colitis was established. On the 70 th day,the mice were executed and colone samples were collected. Disease activity index（ DAI）,colon length and pathological inflammation score of the colon were recorded. The expression levels of pro-inflammation cytokines（ IL-6,IL-8,and TNF-α）,IRE1α,and RIG-I mRNA were detected by real-time quantitative PCR,and the expression levels of p-IRE1α and RIG-I protein were assessed by immunohistochemistry and Western blot. Results：There was no inflammation in colon of control group,whereas in the chronic colitis group the colon showed inflammatory manifestations at the end of the 3 rd cycle. IL-6,IL-8 and TNF-α mRNA levels in the chronic colitis group were significantly higher than those in control group（ P〈0. 01）; the expression levels of IRE1α and RIG-I mRNA in colon tissue of the chronic colitis group were significantly lower than those of control group（ P〈0. 01）. p-IRE1α protein was mainly expressed in the cytoplasm of colonic epithelial cells,and plasma cells; RIG-I protein was mainly expressed in colonic epithelial cells and interstitial cells. Conclusion：RIG-I might be involved in intestinal inflammatory process by the inhibition of IRE1-RIDD-RIG-I pathway of the mice.